Abstract: Melt-spun filaments having a highly crimped configuration which is imparted by differential cooling, nonwoven webs of the crimped melt-spun filaments, and a process of forming a nonwoven web of the crimped filaments are disclosed. The filaments are formed from a random copolymer of propylene and ethylene or an alpha-olefin co-monomer having at least 4 carbon atoms which provides an enhanced response to filament crimping by differential cooling. The random copolymer may contain from about 0.5 to about 10 percent, by weight, of ethylene or an alpha-olefin co-monomer having at least 4 carbon atoms; and from about 99.5 to about 90 percent, by weight, propylene. The alpha-olefin co-monomer having at least 4 carbon atoms may be 1-butene, 4-methyl-1-pentene, 1-hexene, or 1-octene.